Author Topic: Just electrocuted myself  (Read 21227 times)

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Offline Psi

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Re: Just electrocuted myself
« Reply #25 on: December 04, 2015, 06:45:45 am »
Just because a lot of people decided to use the word wrong doesnt mean i have to accept it   :box:   :-DD
Greek letter 'Psi' (not Pounds per Square Inch)
 

Offline coppice

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Re: Just electrocuted myself
« Reply #26 on: December 04, 2015, 06:48:47 am »
This quote from stack exchange sums it up the best:
"While the term electrocute was originally coined in 1889¹ to mean execution by electric shock, its meaning has evolved over time: first to also include accidental death by electric shock and later to include electrical injury,² generally serious in nature. So your use of the word does not fit the 19?? century coined meaning, but is perfectly in line with the broader meaning of the word as it is understood today."
When did the ramblings on stack exchange become a measure of correct English? People there rarely get in the ballpark of a useful technical answer, let alone a linguistic one.
 

Offline Shock

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Re: Just electrocuted myself
« Reply #27 on: December 04, 2015, 07:04:47 am »
When did the ramblings on stack exchange become a measure of correct English? People there rarely get in the ballpark of a useful technical answer, let alone a linguistic one.

Good point but it doesn't make it any less true, the English language is still accepting new words and new meanings for words last time I checked.

Case in point, "crutch" is now acceptable as the same word as "crotch", so many people messed this one up whole nations probably said the wrong word.

When people say "she fell on her fanny" I go :wtf: is that even possible?
« Last Edit: December 04, 2015, 07:26:26 am by Shock »
Soldering/Rework: Pace ADS200, Pace MBT350
Multimeters: Fluke 189, 87V, 117, 112   >>> WANTED STUFF <<<
Oszilloskopen: Lecroy 9314, Phillips PM3065, Tektronix 2215a, 314
 

Offline station240

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Re: Just electrocuted myself
« Reply #28 on: December 04, 2015, 08:50:46 am »
I got a shock from a 100uF 400V cap, two things that caused this:
1. The two circuits have a common ground, the negative of the 400V cap goes through to the LV output.
2. I miswired the output of the capacitor, so the positive went to the negative of the second circuit.

I had alligator clips on the LV side of the second circuit, to measure the voltages. Copped a belt from the negative when I tried to change the connections to measure another rail.

Still nothing compared to the time I bridged active to earth when my finger found it was into the back of a 240V switch.
 

Offline nukieTopic starter

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Re: Just electrocuted myself
« Reply #29 on: December 04, 2015, 11:16:21 am »
Just because a lot of people decided to use the word wrong doesnt mean i have to accept it   :box:   :-DD
Now how do I edit the title again?? [emoji12]
 

Offline dom0

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Re: Just electrocuted myself
« Reply #30 on: December 04, 2015, 04:39:21 pm »
assumed that

"Assumption is the MOTHER of all fuck ups!"

(I actually like the German translation better: "Der Anfang jeder Katastrophe ist eine beschissene Vermutung.", it doesn't sound so offensive and makes a better everyday quote)
,
 

Offline Mechatrommer

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Re: Just electrocuted myself
« Reply #31 on: December 04, 2015, 04:39:34 pm »
"electrocuted" is a contemporary word, just like it used to mean death by electric chair then death by electric shock, it now can mean either a fatal or non fatal shock, look up a few dictionaries for evidence of this.
i think sheet literally means ones dropping but people used everywhere in any cases... people said... talk out of your arse... well, how's that even possible? a ticket is a pass to cinema or concert, but why it is used for something you have to pay? it should be an invoice. for example... the traffic police officer gave me an invoice because i drip and drive.
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 

Offline cncjerry

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Re: Just electrocuted myself
« Reply #32 on: December 04, 2015, 06:14:01 pm »
Normally it's not the shock that hurts you but the extraction.

I moved into a new apartment and it was hot as hell.  I took a shower and turned on the A/C that wasn't working.  I thought it was the capacitor on the motor.  So while dripping wet, I reached into the fan box to give it a spin while holding onto the frame.  I got a big, big, shock as the 220v motor was shorted.  While pulling my arm out of the fan box I got my arm against the cutout and got a nasty cut.  I bounced all over that little space from the shock.  I think I was out for a minute or two.  Pretty close one. Put that on the list of things to not do in the future.

Jerry
 

Offline eugenenine

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Re: Just electrocuted myself
« Reply #33 on: December 05, 2015, 12:58:36 am »
I don't know, which one I hate more, DC or AC... I guess the one, where I had the least resistance/capacitance against at that moment, they both suck  :--

A slow 30Hz AC from a (telephone) ring generator is the worst.  It just doesn't shock you and kick you away, it pulses slowly so it shocks you over and over again.
 

Offline UPI

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Re: Just electrocuted myself
« Reply #34 on: December 07, 2015, 02:14:01 pm »
How many people have been bitten by the anode on the back of an old colour TV CRT?  That hurts.


Did that about 30 years ago. Worst shock of my life. I quickly sat down on the floor to prevent a fall.

 

Offline lm3baker

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Re: Just electrocuted myself
« Reply #35 on: December 08, 2015, 01:28:29 am »
I was trying to dissect a 12v wall adapter, assumed that bleed resistor has done its job. Removed the board from the butchered plastic welded casing and instantly zap myself. It was quite painful and shocking from a pair of little 10uF 400v mains cap.

Unfortunately the circuit wasn't exposed so I didn't discharge the caps. Next time I'll wear gloves and definitely not look down on little caps!! Repaired many LCD and smps and yet still get zap. Please be safe when making repairs or dissection.

I'm very wary of those things, once unplugged one and placed it down on a bench, the two plug prongs hit a metal object and "crack" - the prongs were quite live after being unplugged. That particular power supply failed about a month later. Another time was pulling one out of the socket and the lousy thing came apart in my hands, fortunately the switch at the outlet was off, but 430V DC hurts. Needless to say that wall-wart was disposed of immediately, although failure analysis was that the self-tapping screw holding the housing together was undersized, leaving a single solder joint to do the job.
« Last Edit: December 08, 2015, 01:30:31 am by lm3baker »
 

Offline voltz

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Re: Just electrocuted myself
« Reply #36 on: December 08, 2015, 01:53:47 am »
Easy to say now, but we all have to be careful! Get that test meter out and always check caps before touching anything! Always assume a cap is charged. 50v is the safety max, get it below that, the lower the better.. It becomes a habbit, second nature. Glad you're ok!
 

Offline Mechatrommer

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Re: Just electrocuted myself
« Reply #37 on: December 08, 2015, 02:04:19 am »
really on the cheap? no need meter... just a 1Kohm bleed resistor connected for a few seconds...
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 

Offline Brumby

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Re: Just electrocuted myself
« Reply #38 on: December 08, 2015, 02:14:47 am »
As a hobbyist, I didn't end up working on too many TV's and when I did, I looked at everything inside as wanting to kill me.  Reading the Serviceman column in EA gave me a lot of good information - especially of the things that could go wrong ... and the one hand in the pocket rule.

There was, however, one time when I was building the Playmaster 132 project out of EA.  My father worked in the office of an engineering business that had all the metal fabrication gear you could wish for, so I was able to get the chassis made up as a 'foreign order'.  I was also able to get a front panel cut (made from food grade stainless steel) to which I added Letraset, giving a fantastic result.

During the final stages of the build, I had the unit plugged in and picked it up by the chassis to turn it over when I felt this sharp pain in my fingertip that felt (as I might imagine) like a huge spider had dug its fangs into me.  There was no other discomfort.  I quickly put the chassis down and inspected my fingertip to see two little black marks.  Yep - they were burns.  So I unplugged the unit and sat back for a few minutes contemplating what had happened and wondering how, until I gained the confidence to approach the unit again.

The answer was very obvious when I check the AC power switch.  When I had wrapped my hand around the chassis, the affected fingertip had gone underneath and made contact with the exposed switch contacts.  The 240v then travelled less than 1 cm to the chassis which was securely earthed, saving me from a worse fate.

Ever since then, I have had a healthy respect for one fundamental construction technique - when you have your mains wiring secured, tested and ready to rock - WRAP IT UP.
 

Offline SL4P

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Re: Just electrocuted myself
« Reply #39 on: December 08, 2015, 03:21:59 am »
really on the cheap? no need meter... just a 1Kohm bleed resistor connected for a few seconds...
Yerp, just hold the two pigtails against the device to be discharged... (NOT!! )
Don't ask a question if you aren't willing to listen to the answer.
 

Offline Mechatrommer

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Re: Just electrocuted myself
« Reply #40 on: December 08, 2015, 10:33:58 am »
really on the cheap? no need meter... just a 1Kohm bleed resistor connected for a few seconds...
Yerp, just hold the two pigtails against the device to be discharged... (NOT!! )
i didnt say use your hand on the metal leads, i did say however... use your brain, didnt i?
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 

Offline SL4P

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Re: Just electrocuted myself
« Reply #41 on: December 08, 2015, 11:05:05 am »
really on the cheap? no need meter... just a 1Kohm bleed resistor connected for a few seconds...
Yerp, just hold the two pigtails against the device to be discharged... (NOT!! )
i didnt say use your hand on the metal leads, i did say however... use your brain, didnt i?
I werz jowking- if ennywun thort that eyedea wuz furreal... well  :-\
Don't ask a question if you aren't willing to listen to the answer.
 

Offline Mechatrommer

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Re: Just electrocuted myself
« Reply #42 on: December 08, 2015, 11:15:13 am »
no fear... i'm a robot. an emotion is a very weird concept... ;)
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 

Online mikerj

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Re: Just electrocuted myself
« Reply #43 on: December 08, 2015, 05:37:54 pm »
I had an unpleasant experience many years back working on my brothers car (classic mini).  It had an ignition problem and I'd removed the king lead from the ignition coil, and then pulled off one of the primary (aka 'low tension') connections.  Unfortunately I didn't realise the ignition was switched on, and pulling off the primary connection caused a large spark to leap out of the coil and ground through my hand.  The muscle contraction then forced me to touch the primary connection back onto the coil, another spark, another muscle contraction.... After about ten shocks I managed to break the cycle by collapsing onto the ground.
 

Online Ian.M

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Re: Just electrocuted myself
« Reply #44 on: December 08, 2015, 09:04:39 pm »
Ah yes, the joys of stopping a lawnmower or outboard by shorting the HT with your hand!
 

Offline SpidersWeb

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Re: Just electrocuted myself
« Reply #45 on: December 08, 2015, 09:47:48 pm »
With caps on mains stuff these days I actually do a quick measurement with a multimeter - not because of fear/danger but more because I don't like surprises.

First time I got the mains I was a teenager and learned that some manufacturers think it's hilarious to put the power switch on neutral and not the phase. Now I remember to unplug and check :P Haven't had a proper shock in 10 years.
 

Offline nukieTopic starter

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Re: Just electrocuted myself
« Reply #46 on: December 09, 2015, 11:07:45 am »
Finally have time to continue with the taser wannabe wall adapter. I can confirm the 1/4w 1.5Mohm bleed resistor has gone open circuit. There's no indication whatsoever the part looks fine but ohmmeter tells another story.

Moral of the story never rely on bleed resistor. Wait a day or two for the caps to discharge if there is no means of discharging them.
 

Offline Mechatrommer

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Re: Just electrocuted myself
« Reply #47 on: December 09, 2015, 05:38:59 pm »
or dont open it at all... "certified personnel only". if you dont know how to bleed, you are not certified...
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 

Offline nukieTopic starter

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Re: Just electrocuted myself
« Reply #48 on: December 10, 2015, 04:32:16 am »
How do you bleed a circuit without direct access to the pcb?!
 

Offline NilByMouth

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Re: Just electrocuted myself
« Reply #49 on: December 10, 2015, 10:16:55 am »
My last electric shock was back in the 80's when I grabbed an adapter connected to a 1KV DC calibrator (which had little to no current limit) that had been left on by the last person who used it. I had a lot more respect for electricity after that. If I had grabbed it with both hands I might not be here now to post this.
 


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